D2 aux fan runs all the time

[ubuntu]

The aux fan starts up as soon as I turn the key to the aux position - this is a cold engine that's not running. As soon as there is power the fan runs.
I pulled the fan relay and swapped with another, fan stops without a relay in and then starts up with the swapped relay.
Guessing an incorrect temp reading somewhere?

 

[JohnB]

I'd look for a wire that has grounded on the frame. Seems like those relays are negative activated by the BCU. So if that wire grounded somewhere then the fan would be on all the time.
BCU operates that fan and takes into account, all kinds of data. Speed of vehicle, outside air temp, engine temp,
Overly complicated for something that has little effect on anything other than pushing air on the evaporator at idle.

 

[AfiRover]

does your AC blow "cold air" or cool air ?

 

[ubuntu]

AC blows cold air. Will double check just to be sure, but I did a quick check.

 

[AfiRover]

you might try this

The ATC ECU performs a diagnostic check each time the ignition is switched on. To avoid nuisance fault indications at low light levels, the sunlight sensor is omitted from the diagnostic check. If a fault is detected, the audible warning sounds three times and the AUTO window on the control panel display flashes for 20 seconds. The ATC ECU then reverts to normal control but uses a default value or strategy for the detected fault. Faults are identified by performing a manual diagnostic check of the system. A manual diagnostic check includes a check of the sunlight sensor, and is initiated by pressing and holding the AUTO switch and the air distribution switch, then turning the ignition switch from off to on. The audible warning sounds once and the indications on the control panel display illuminate. FC is shown in the LH temperature window and the results of the check are shown as a two digit fault code in the RH temperature window. If a fault is detected, the audible warning sounds three times and the AUTO window on the display flashes on and off for 20 seconds. If more than one fault is detected, the fault codes cycle in numerical order, at 1 Hz. The audible warning sounds as each fault code is shown. In low light conditions, to avoid false sunlight sensor fault indications, the sunlight sensor should be illuminated with a strong light source.

codes are as follows

Diagnostic fault codes and fault descriptions
Code Component Fault Default value/strategy
00 No fault found
11 In-car temperature sensor Open or short circuit 25°C (77°F)
12 Ambient temperature sensor Open or short circuit 10°C (50°F) Cooling fan permanently on Display shows "- -" if external air temperature selected
13 Thermistor Open or short circuit 0°C (32°F)
14 Heater coolant temperature sensor Open or short circuit 70°C (158°F)
21 Sunlight sensor, left output Open or short circuit No solar heating correction
22 Sunlight sensor, right output Open or short circuit No solar heating correction
31 LH temperature servo motor Open or short circuit Motor or flap mechanism seized Servo motor locked in position
32 RH temperature servo motor Open or short circuit Motor or flap mechanism seized Servo motor locked in position
33 Distribution servo motor Open or short circuit Motor or flap mechanism seized Servo motor locked in position

and report back

 

[ubuntu]

Code 21 and 22.
The car is parked in the garage at the moment.

 

[AfiRover]

measure at the fan relay and see if is stuck on?

 

[ubuntu]

I swapped relays - I thought that would eliminate a stuck relay?

 

[AfiRover]

ok try this get a bag of ice and some water insert the temp sensor that's behind the grill see if they shut off ?

 

[Devildog01]

Let it run. It's not like rover's are prone to overheat or anything.

 

[slangel]

Tillery noticed that mine was doing it the other day, I apparently need to turn my radio down sometimes I discovered that mine was a grounding issue.

 

[ubuntu]

It resolved itself after I cleaned the battery terminals and battery cables, must have been a grounding issue.